1. Field of the Invention
The present invention relates to a porous absorbent capable of absorbing ink or the like, and also, relates to an ink jet recording apparatus provided with such porous absorbent. As a specific example, the present invention is applicable to an ink absorbent used for absorbing waste ink exhausted from an ink jet recording apparatus, and to the ink jet recording apparatus, which is provided with such waste ink absorbent.
2. Related Background Art
The ink jet recording method is widely utilized for a printer or a copying machine, because the method makes it easier to downsize the apparatus, which can operate with a lesser amount of noise at a lower running cost, and also, makes it easier to provide color prints. When using the ink jet recording apparatus, however, there may be encountered defective discharge (including disabled one) if ink discharge port is clogged by the adhesion of foreign substance, such as paper fluff or dust particles, to the ink discharging portion of a recording head or if ink adhering to the discharging portion is dried to make it overly viscous or solidified. Also, when a new ink cartridge or a head cartridge is used, the ink flow path from the ink discharge port to the ink tank is not necessarily in the normal condition. Therefore, in order to prevent the ink discharge port from being clogged or to normalize the ink flow path, there is provided cleaning means for removing foreign substance that adheres to the ink discharge portion (such as the formation surface of ink discharge ports) or recovery means for implementing the normalization of the ink flow path of the ink discharge port of the recording head. As cleaning means, there is adopted a mechanism that wipes and cleans the formation surface of the discharge port of a recording head mainly by use of a flexible wiper (wiping member).
Also, as recovery means, a recovery device is used for closely capping the formation surface of a discharge port of a recording head mainly when recording is not in operation so as to cover the ink discharge port by use of a cap (hereinafter, may also be referred to as “to execute capping”), while sucking ink from the ink discharge port through the cap by use of suction means, such as a pump. The recovery device exhausts the ink, which is no longer suitable for recording, to a waste-ink container arranged on the downstream side of the suction means. In this manner, the recovery operation is performed to implement the normalization of the ink discharge port or ink flow path. As the pump that forms the suction means, there are practically in use a pump of cylinder piston type, a pump that utilizes the deformation of a cap made of elastic material, and a tube pump or the like. Among them, the tube pump is widely used as suction means for a printer of disk top type, because it has a wider range within which it can recognize the suction pressure or suction amount so that the suction pressure or suction amount can be set comparatively freely by use of a pump of one and the same structure with a high adaptability to various kinds of products, although it is not suitable for use aiming at downsizing like a pump of the cylinder piston type. Also, in the waste ink container, there is at least provided a waste ink absorbent in order to retain waste ink exhausted from the pump.
At present, the waste ink absorbent that is installed for the recording apparatus is formed by 100% virgin cellulose fiber.
However, the waste ink absorbent formed by 100% virgin cellulose fiber is expensive. Also, in order to enable the waste ink absorbent to sufficiently demonstrate its ink collection capability, a structure, such as disclosed in the specification of Japanese Patent Laid-Open Application No. 2000-135797, is adopted so that a sheet layer of synthetic fiber is laminated on the surface of the waste ink absorbent, for example. In this case, the structure of the waste ink absorbent becomes complicated, which invites more increase of costs inevitably.
Now, along with the advancement of technologies, environmental consideration is prerequisite, and the recycling capability of a product or the reusability thereof should be considered more. From the viewpoint that such trends should be taken into account, studies have been made assiduously to reconsider the structure of waste ink absorbent using virgin cellulose fiber. Conceivably, it is possible to utilize recycling or recycled material, such as used paper, positively for the structure of waste ink absorbent with the environmental problem in view.
In the course of the studies thus made, it has been found that a buffer that absorbs shocks given to a product at the time of distribution or delivery is a structure formed by the utilization of cellulose fiber such as used paper. For such buffer, there are the one produced in a dry method of manufacture as disclosed in the specification of Japanese Patent Laid-Open Application No. 9-78500 (U.S. Pat. No. 5,785,817) and those produced by wet methods of manufacture as disclosed in the specifications of Japanese Patent Laid-Open Application No. 2000-119999 and Japanese Patent Laid-Open Application No. 2000-120000, among some others. Here, however, if a buffer produced by the dry method is used as a waste ink absorbent, the bound fibers themselves are peeled off when absorbing ink and the shape of the buffer is collapsed to pieces. A buffer of such kind is not high in the ink absorbing capability fundamentally, and it cannot absorb waste ink as sufficiently as anticipated. This material is not satisfactory when used as the waste ink absorbent for an ink jet recording apparatus. On the other hand, the buffer produced by a wet method has a good ink absorbing capability as compared with the one produced by the dry method. Nevertheless, when absorbing ink, the buffer becomes breakable so as to make it difficult to handle, because the shape thereof is easily collapsed.
After all, although the material that has been proposed as the buffer utilizes recycling material, such as old paper, in consideration of the environmental problems, the shape of such material collapses easily to make its handling capability inferior. The ink absorption that such material can perform is not sufficient, either. Consequently, it is found impossible to use such material as an ink absorbent for an ink jet recording apparatus.
Now, assuming that such buffer is installed as the waste ink absorbent for an ink jet recording apparatus, there is a fear that the waste ink absorbent is partly collapsed to lose the original shape thereof when such waste ink absorbent is installed before absorbing waste ink (that is, at the time of installation thereof in the manufacturing step of an ink jet recording apparatus) and when the waste ink absorbent is collected after having absorbed waste ink (that is, at the time of collecting the waste ink absorbent for disassembling the ink jet recording apparatus for recycling). Further, the collapsed minute portions of the waste ink absorbent at the time of installation reside in the ink jet recording apparatus as dust particles eventually, which may cause the function of ink jet recording head, the essential part of an ink jet recording apparatus, to be deteriorated, thus resulting in the lower quality of recorded images. Also, the collapsed minute portions of the waste ink absorbent reside as remainders in the ink jet recording apparatus at the time of the recycling operation, which may stand in the recycling performance of the ink jet recording apparatus.
There is also a fear that the waste ink, which has not been absorbed by waste ink absorbent formed by the buffer, the ink absorptive performance of which is inferior, leaks from the portion where the waste ink absorber is contained when such buffer is used as the waste ink absorber for an ink jet recording apparatus. Further, there is a fear that the containing portion of such waste ink absorber presents discoloration due to contact with the waste ink that has not been absorbed by the waste ink absorber for a long time if the waste ink containing portion is formed by synthetic resin, and that the recycling thereof becomes impossible. Particularly, when the containing portion of such waste ink absorbent is formed as a part of the housing of the apparatus main body, there is a fear that the recycling possibility of the entire housing is lost.
Also, the conventional waste ink absorbent is formed by unwoven fibrous cloth. Therefore, the fiber that forms the absorbent becomes fine feather-like fluff, and there is a fear that such fluffs scatter in an ink jet recording apparatus. Such scattered fluffs may in some cases spoil the function of the ink jet recording head, which is the essential part of an ink jet recording apparatus, resulting in the lowered quality of recorded images.